Optimization of Kefir Fermentation for Kefiran Production

Kefir is native fermented milk derived from the Caucasian. It has sour taste and alcoholic qualities caused by the fermentation of yeast and bacteria embedded in kefir grain. By fermenting the kefir, lactic acid bacteria in the grain produce the viscous polymer called kefiran. Kefiran was produced from kefir grains via fermentation with coconut juice or fresh milk. It was found that kefir grains in milk produced higher amounts of kefiran and lactic acid than kefir grains in coconut juice while kefir grains in coconut juice produced higher amount of ethanol. It was also found that at 30ºC, kefir grains in coconut juice produced higher amount of kefiran, lactic acid and ethanol than at 37 °C. Additionally, the initial seed inoculum of kefir grains in milk at 1% of kefir grain wet weight by milk volume in static condition yielded the highest amount of kefiran at 73.63 mg per 120 mL of milk. The optimal conditions obtained in this study may contribute to the production of kefiran through kefir fermentation.